Electrochemical determination of ammonia at low concentrations

A Pt nanoparticle catalyst supported on partially-defective CeO₂ was developed for sensitive voltammetric detection of ammonia (NH₃) in alkaline media (0.5 mol dm⁻³ NaOH), achieving a detection limit of 2–3 μmol dm⁻³. This system enables in situ NH₃ monitoring during nitrogen electroreduction at an Fe₃P catalyst, without medium transfer, minimizing contamination. The Pt-based electrode also serves as a diagnostic tool to confirm electrolyte and gas purity. Selective NH₃ formation with negligible hydrazine or hydroxylamine by-products was confirmed via voltammetry and spectrophotometry.